Significant progress in lifetimes and fidelity of superconducting transmon qubits have been realized over the last decade and yet two-level system (TLS) defects continue to be a dominant source of noise and decoherence. The exact source of TLS defects is not well understood, but it is believed to be associated with a number of defects in the material including charge fluctuators, dangling bonds and various other quasiparticle generators. An atomic level understanding of the location, size, and distribution of these TLS defects in superconducting qubits and their materials would achieve a major milestone in the quest to mitigate and eliminate the impact of TLS defects on qubit performance. The objective of this research is to discover the causation and correlation of TLS defects on superconducting qubit devices, by means of a low temperature (1.5 K) scanning probe microscope fitted with a ST magnet, and electrical biasing and excitation sources including 45 GHz RF and multiple DC lines, and demonstrate mitigation techniques through materials engineering.
The Laboratory for Physical Sciences (LPS) currently has an opportunity for post-doctoral research in basic physics. In an effort to identify and mitigate against TLS in superconducting qubits, LPS invites candidates with expertise in surface science and related experimental techniques. Extensive experience in scanning probe microscopy is required. Prior experience with RF measurements, electron spin resonance (ESR), and superconducting qubits would be ideal. This effort operates within a team dedicated to fostering a collaborative environment for research with broad expertise in surface science, materials science and characterization, cryogenic measurements, RF engineering, and device fabrication.
LPS is well equipped for cutting-edge research with a state-of-the-art clean room for device fabrication, a full service machine shop staffed with professional machinists, advanced microscopy and imaging tools, multiple STM tools, SEM, AFM, XRD, scanning XPS/Auger and much more. Work is done in close collaboration with academia, other government labs, and industry.
scanning probe microscopies; qubit performance; materials defects; STM-ESR; superconducting devices;
Additional Benefits
Relocation
Awardees who reside more than 50 miles from their host laboratory and remain on tenure for at least six months are eligible for paid relocation to within the vicinity of their host laboratory.
Health insurance
A group health insurance program is available to awardees and their qualifying dependents in the United States.